Notes on Valgrind
=================

Valgrind is a test harness that includes many tools such as memcheck,
which is commonly used to check for memory leaks, etc. The default tool
run by Valgrind is memcheck. There are other tools available, but this
will focus on memcheck.

Valgrind runs programs in a virtual machine, this means OpenSSL unit
tests run under Valgrind will take longer than normal.

Requirements
------------

1. Platform supported by Valgrind
   See <http://valgrind.org/info/platforms.html>
2. Valgrind installed on the platform
   See <http://valgrind.org/downloads/current.html>
3. OpenSSL compiled
   See [INSTALL.md](INSTALL.md)

Running Tests
-------------

Test behavior can be modified by adjusting environment variables.

`EXE_SHELL`

This variable is used to specify the shell used to execute OpenSSL test
programs. The default wrapper (`util/wrap.pl`) initializes the environment
to allow programs to find shared libraries. The variable can be modified
to specify a different executable environment.

    EXE_SHELL=\
    "`/bin/pwd`/util/wrap.pl valgrind --error-exitcode=1 --leak-check=full -q"

This will start up Valgrind with the default checker (`memcheck`).
The `--error-exitcode=1` option specifies that Valgrind should exit with an
error code of 1 when memory leaks occur.
The `--leak-check=full` option specifies extensive memory checking.
The `-q` option prints only error messages.
Additional Valgrind options may be added to the `EXE_SHELL` variable.

`OPENSSL_ia32cap`

This variable controls the processor-specific code on Intel processors.
By default, OpenSSL will attempt to figure out the capabilities of a
processor, and use it to its fullest capability. This variable can be
used to control what capabilities OpenSSL uses.

As of valgrind-3.15.0 on Linux/x86_64, instructions up to AVX2 are
supported. Setting the following disables instructions beyond AVX2:

`OPENSSL_ia32cap=":0"`

This variable may need to be set to something different based on the
processor and Valgrind version you are running tests on. More information
may be found in [doc/man3/OPENSSL_ia32cap.pod](doc/man3/OPENSSL_ia32cap.pod).

Additional variables (such as `VERBOSE` and `TESTS`) are described in the
file [test/README.md](test/README.md).

Example command line:

    $ make test EXE_SHELL="`/bin/pwd`/util/wrap.pl valgrind --error-exitcode=1 \
        --leak-check=full -q" OPENSSL_ia32cap=":0"

If an error occurs, you can then run the specific test via the `TESTS` variable
with the `VERBOSE` or `VF` or `VFP` options to gather additional information.

    $ make test VERBOSE=1 TESTS=test_test EXE_SHELL="`/bin/pwd`/util/wrap.pl \
       valgrind --error-exitcode=1 --leak-check=full -q" OPENSSL_ia32cap=":0"